Theoretical calculations of interfacial properties of high carbon alcohol-hydrocarbon-ethanol-water systems

To obtain the interfacial properties of the system of high carbon alcohol-hydrocarbon mixture extracted by ethanol aqueous solution, theoretical calculations of different high carbon alcohol-hydrocarbon-ethanol-water systems were carried out using the concentration gradient theory (CGT). The results reveal that the high carbon alcohol-hydrocarbon-ethanol-water quaternary system exhibits an enrichment phenomenon of high carbon alcohol and ethanol in the interface and the average relative error between the calculated interface tension values and the experimental measurement values is 13.22 %. It was found that the closer the distribution coefficient is to 1, the higher the high carbon alcohols enrichment degree. In the heptanol system, when the distribution coefficient changes from 0.94 to 0.53 and 2.00, the enriched area decreases from 0.0577 to 0.0289 and 0.0352, respectively. When the mass fraction of high carbon alcohol in the high carbon alcohol-hydrocarbon mixture changes, the interfacial tension is mainly affected by the enrichment of high carbon alcohol in the interface, the higher the enrichment of high carbon alcohol, the lower the interfacial tension; When the solvent ratio and the carbon number of high carbon alcohol changes, the interfacial tension is mainly affected by the concentration of ethanol and high carbon alcohol in the raffinate phase, the higher the concentration of ethanol and high carbon alcohol in the raffinate phase, the higher the polar force of the raffinate phase and the lower the interfacial tension.